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Themes in Microbiology

LECTURES IN MICROBIOLOGY. Themes in Microbiology. Sofronio Agustin Professor. LESSON 1. Topics Covered. Scope of Microbiology Importance of Microorganisms Characteristics of Microorganisms History of Microbiology Taxonomy. Scope of Microbiology. Microbiology

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Themes in Microbiology

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  1. LECTURES IN MICROBIOLOGY Themes in Microbiology Sofronio Agustin Professor LESSON 1

  2. Topics Covered • Scope of Microbiology • Importance of Microorganisms • Characteristics of Microorganisms • History of Microbiology • Taxonomy

  3. Scope of Microbiology Microbiology • study of organisms too small to be seen by the naked eye. Microbes or Microorganisms • commonly referred to as “germs” or “bugs” • include bacteria, viruses, fungi, algae, protozoa and helminths. • Prions (“infectious proteins”) are recent addition.

  4. Branches of Study • Bacteriology study of bacteria • Mycology study of fungi and yeast • Virology study of viruses • Parasitology study of parasitic protozoans and helminths • Immunology study of the humoral and cellular immune response to disease agents and allergens

  5. Epidemiology and Public HealthMicrobiology distribution and spread of diseases and their control and prevention • Food Microbiology use of microbes in the production of food products and drinks • Agricultural and Veterinary Microbiology use of microbes to increase crop and livestock yield and control of plant pests and animal diseases • Environmental Microbiology study of the beneficial and harmful effects of microbes on the environment Specializations in Microbiology

  6. Importance of Microbiology • First bacteria • Photosynthesis and decomposition • Human use of microorganisms • Infectious diseases

  7. The Progenote Evolutionary Timeline: Bacteria appeared 3.5 billion years ago

  8. Photosynthetic Microbes • Microbes are involved in photosynthesis and accounts for >50% of earth’s oxygen. • Also involved in decomposition and nutrient recycling.

  9. Beneficial Uses of Microbes Extraction of copper from ore

  10. Beneficial Uses of Microbes Synthesis of drugs, hormones and enzymes

  11. Beneficial Uses of Microbes Bioremediation is the use of microbes to degrade organic matter in sewage and detoxify pollutants such as oil spills.

  12. Modern Uses of Microbes • Biotechnology, the use of microbes as miniature biochemical factories to produce food and chemicals is centuries old. • Genetic engineering makes use of molecular biology and recombinant DNA techniques as new tools for biotechnology. • Gene therapy replaces missing or defective genes in human cells through genetic engineering. • Genetically modified bacteria are used to protect crops from pests and freezing.

  13. Infectious Diseases • United States Public Health Service (USPHS) - agency where notifiable diseases are reported • Centers for Disease Control (CDC)-collects disease data around the U.S. and publishes the MMWR (Morbidity and Mortality Weekly Report) • World Health Organization (WHO)-medical arm of the U.N., monitors diseases worldwide. Worldwide infectious disease statistics

  14. Microbial Taxonomy Traditional Whittaker 5 Kingdom System

  15. Microbial Taxonomy Woese-Fox 3 Domain System

  16. Nomenclature • Linnaeus introduced the binomial system of scientific nomenclature • Each organism has two names: the genus and species epithet • Italicized or underline • Genus name is capitalized and species in lower case.

  17. Scientific Names Staphylococcus aureus describes clustered arrangement of cells and golden yellow color of colonies Escherichia coli Honors the discoverer, Theodor Escherich and describes its habitat, the colon. After the first use, scientific names may be abbreviated with the first letter of the genus and full species epithet. (Ex: E. coli)

  18. General Characteristics • Prokaryotes no nucleus and organelles • Eukaryotes membrane bound nucleus and organelles • Acellular agents genomes contain either DNA or RNA; newer agent is proteinaceous

  19. Cell Types Comparative cellular structures of microbes

  20. The Microbes viruses protozoa bacteria bacteriophage algae cyanobacteria spirochaetes fungi

  21. Size of Microbes Microbes vary in size ranging from 10 nm (nanometers) to 100 mu (micrometers) to the macroscopic. Viruses in nm = 10-9 m (meter) Bacteria in um = 10-6m Helminths in mm = 10-3m

  22. Bacteria • Prokaryotes • Peptidoglycan cell walls • Binary fission • Ex: Escherichia coli

  23. Archaea • Prokaryotes • Lack peptidoglycan • Live in extreme environments (extremophiles) Include: • Methanogens • Extreme halophiles • Extreme thermophiles

  24. Fungi • Eukaryotes • Chitin cell walls • Molds and mushrooms are multicellular • Yeasts are unicellular

  25. Protozoa • Eukaryotes • Mostly saprobes and commensals • May be motile by means of pseudopod, cilia or flagella

  26. Algae • Eukaryotes • Cellulose cell walls • Photosynthetic • Produce molecular oxygen and organic compounds • Part of food chain

  27. Helminths • Eukaryotes • Multicellular animals • Parasitic flatworms and roundworms called helminths • Microscopic stages in life cycles

  28. Viruses • Acellular • Obligate intracellular parasites • Genome consist of DNA or RNA called Core • Core surrounded by protein coat called Capsid • Virion may be enclosed in lipid envelope

  29. Prions • Proteinaceous infectious agents • Causes Bovine Spongiform Encephalopathy (BSE) • Also causes Creutzfeldt-Jacob Disease (CJD) • An Emerging Infectious Disease (EID)

  30. Microbiology As A Science • Science a systematized body of knowledge explaining the occurrence of natural phenomena • Qualities of a scientist: curiosity open-mindedness skepticism creativity objectivity

  31. Scientific Approach • Deductive reasoning starts with a general idea that are tested to prove or disprove it. • Inductive reasoning starts with drawing patterns from specific observations resulting in generalization.

  32. Scientific Method • Hypothesis • Laboratory experimentation or field Studies • Data collection and analysis • Conclusion, either reject or accept hypothesis • Theory or Law

  33. Microbiological Experiment

  34. Brief History of Microbiology • The Microscope • Spores and Sterilization • Spontaneous Generation • Aseptic Technique • Germ Theory

  35. The First Microscope Microbes were first observed by Antonie van Leeuwenhoek using a simple microscope (ca. 1673) Reported his “animalcules” to the Royal Society of London

  36. Spores and Sterilization • John Tyndall showed that some microbes in dust and air were resistant to heat. • Ferdinand Cohn discovered and described endospores • Term “sterile” was introduced to mean the complete removal of all life forms including endospores

  37. Abiogenesis vs. Biogenesis • “Spontaneous Generation” was an early belief that living things can arise from vital forces present in nonliving and decaying matter. (Ex: maggots from meat or mushrooms from rotting wood • The alternative hypothesis that living organisms can arise only from preexisting life forms is called “Biogenesis”

  38. The Pros and Cons Francisco Redi (ca. 1668)

  39. The Pros and Cons • 1745 -John Needham boiled nutrient broth into covered flasks From where did the microbes come? Spontaneous generation or biogenesis?

  40. The Pros and Cons Louis Jablot

  41. The Pros and Cons Franz Schultze and Theodor Schwann

  42. The Pros and Cons Louis Pasteur put an end to Abiogenesis debate with his Goose Neck Flask Experiment He is the father of Microbiology

  43. Louis Pasteur • Showed microbes caused fermentation • Studied spoilage and introduced “Pasteurization” to prevent it • Used cotton plugs in his cultures to prevent air borne contamination, devised Aseptic Technique.

  44. Antiseptics and Hand Washing • 1860s - Joseph Lister used, carbolic acid, a chemical antiseptic to prevent surgical wound infections • Ignaz Semmelweis, a Hungarian physician introduced hand washing as a means of preventing transfer of puerpueral sepsis in obstetrical patients

  45. Germ Theory of Disease • 1876 - Robert Koch provided proof that a bacterium causes anthrax using experimental steps now called the Koch’s Postulates • He was the first to use agar as solid culture medium in bacteriology.

  46. Koch’s Postulates • The microbe must always be present in every case of the disease • It must be isolated in pure culture on artificial media • When inoculated into healthy animal host it should produce the same disease • It must be isolated from the diseased animal again

  47. Infection and Disease • Infection the entry of a microbe into the host. • Disease infection followed by the appearance of signs and symptoms. • Pathogen an infectious or disease agent. • Saprobe a microbe that lives on dead or decaying organic matter. • Opportunistic pathogen is a microbe that cause disease in immunocompromised hosts or when the normal microbiota is altered.

  48. Emerging Infectious Diseases • Occurrence of new diseases and increasing incidence of old ones (EID) • Factors: (a) evolutionary changes in existing organisms (b) spread of known diseases into new geographic areas by modern transportation (c ) ecological changes resulting in introduction of unusual agents (d) emergence of antimicrobial resistance

  49. Emerging Infectious Diseases • West Nile Encephalitis, first diagnosed in Uganda in 1937; appeared in New York City in 1999. • Invasive Group A Streptococcus, also known as the “flesh eating bacteria” • Escherichia coli 0157:H7, causes “bloody diarrhea” and hemorrhagic uremic syndrome (HUS) • Bovine Spongiform Encephalopathy (BSE) or “mad cow” disease caused by prions • Acquired Immunodeficiency Syndrome (AIDS) caused by HIV and Africa is hardest hit • Anthrax caused by Bacillus anthracis was sensationalized in 2001 when spores were disseminated via the mail

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